The list goes to only 48 because two states – Nebraska and Utah – did not have data available.

The study also looked at standards for eighth-grade reading proficiency. South Carolina, Missouri, Minnesota, and Vermont are in the top five, as they were for fourth grade. But Massachusetts, which was No. 1 in the list above, dropped to No. 10 for eighth grade. And Florida moved up to the fifth spot.

Only one state from the fourth-grade bottom – Tennessee – repeats in the lowest rankings for eighth grade. The other states bringing up the rear for eighth grade are Georgia, North Carolina, Texas, and West Virginia.

The report includes rankings for mathematics standards, too. The states that set the highest bar for fourth-grade math proficiency in 2007 are:

One thing to keep in mind is that these rankings deal with state standards – not with the actual performance of students. It's conceivable that a state has low standards, yet students there do very well. The reverse – weak performance in a high-standards state – is possible, too.